027
FXUS66 KMFR 120954
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
Issued by National Weather Service Eureka CA
254 AM PDT Sat Jul 12 2025

AVIATION...12/12Z TAFs...VFR conditions are expected for all
areas away from the immediate coast through the TAF period. Along
the coast from Cape Blanco north, LIFR conditions will persist
into Saturday morning. Then, expect clearing to VFR around 18-20Z
except for local IFR continuing for some portions of the coast in
the afternoon. IFR/LIFR will return to areas along the coast from
Cape Blanco northward Saturday evening. Typical diurnal breezes
are expected Saturday, strongest along the coast, with wind speeds
decreasing near/after sunset.

&&

.PREV DISCUSSION... /Issued 1005 PM PDT Fri Jul 11 2025/

DISCUSSION...Satellite shows marine stratus making its way
towards the coast into the Coos Bay and Bandon area. This will
continue tonight before burning off in the morning. Temperatures
will be warmer again tonight with more 50s and 60s. The area is
then on track to see the heat come tomorrow afternoon with triple
digits in some west side valleys. Please see the information in
the previous discussion for more details on the heat and what`s
ahead. -Hermansen

PREV DISCUSSION... /Issued 222 PM PDT Fri Jul 11 2025/

DISCUSSION...The main theme for the next week is `hot and dry.`
This will be due to the main feature of persistent ridging
extending from central and southern California into our region.
This includes easterly winds providing downslope warming for
Brookings (with day-time temperatures in the mid 70s to mid 80s),
likely from now into Tuesday morning. More broadly, the Heat
Advisory and Extreme Heat Warning remain in effect for inland
valleys through Monday evening. Thereafter, there is higher,
though still not high, confidence in around 2 or 3 degrees of
cooling for Tuesday into Wednesday. This cooling would be barely
perceptible, but could be just enough to nudge us below at least
the level of Extreme Heat criteria in Josephine, Jackson, and
western Siskiyou counties. The short term temperature forecast is
consistent with peak heating on Sunday, though perhaps it will be
a degree or so hotter on the east side on Monday...as the thermal
trough tracks inland. West side highs of 95 to 105 will be common,
except highs up to 111 in the Klamath River and Salmon River
valleys in far western Siskiyou County.

The most notable exception to the sunny skies will be areas of
night and morning low clouds and fog from Cape Blanco northward. A
thicker marine layer (with more or much more limited afternoon
clearing of low clouds) is likely for the Coos and Douglas coast
Monday night through Friday night. With temperatures in the 50s
for lows and 60s for highs, the coast (particularly north of Cape
Blanco) will be the most effective place to go to escape the heat.

Also of note, mid-level moisture aloft will mostly be limited and
ridging will provide a stable air mass. But, a few fair weather
cumulus may pop up from day-to-day over the higher terrain. A very
weak trough moving to the coast on Sunday with an embedded
shortwave could be just enough for a thunderstorm or two to pop up
in the evening in western Siskiyou County(with a 15% probability).
Meanwhile, the probability for the same period has kept to 10%
for Klamath County. Otherwise, the 12Z operational GFS is among a
sizable minority of model solutions that do indicate a weak but
broad trough forming offshore and moving slowly east late in the
week. This is still not a very progressive pattern, but by simply
not being stagnant, it makes it worth mentioning that some late
week very slight thunderstorm probabilities could eventually be
needed, with the east side having the highest probability. This
also directly leads to the GFS indicating a few to several degrees
of cooling late in the week, which is absent or at least far more
muted in the blended solution and majority of ensemble members.

Lastly, breezy afternoon westerly winds will be on the light to
typical scale at 10 to 15 mph today and Saturday. But, they will
pick up a bit on the east side on Sunday with 10 to 20 mph speeds
expected to be more common there in the afternoons and evenings
next week.

MARINE...Updated 200 PM PDT Friday, July 11, 2025...The thermal
trough pattern will continue through the weekend and well into next
week. This will maintain strong gusty north winds and steep to very
steep wind driven seas across all waters. Gales are expected in the
afternoons/evenings mainly south of Port Orford and beyond 5 nm from
shore. Very steep and hazardous seas could spread north of Cape
Blanco later Sunday into Monday. Conditions could begin to improve
around mid-week next week. Otherwise, daily conditions will remain
quite similar for the next several days. /BR-y

FIRE WEATHER...Updated 200 PM PDT Friday, July 11, 2025...A
developing upper level ridge is bringing seasonal temperatures
today. Daytime highs increase further on Saturday as the ridge
strengthens, then look to stay 5-10 degrees above normal across the
area through Wednesday. Normal diurnal breezes are expected with
lighter overnight winds. Easterly winds are possible overnight for
coastal ranges as well as the Klamath and Siskiyou mountains, which
may result in moderate to locally poor RH recoveries especially for
ridgetops where overnight gusts exceed 25 mph. Hazardously gusty
winds are not forecast, but the pattern is stable and these dry
conditions are expected to continue through much of the forecast
period.

While significant thunderstorm threats are not part of this period,
upper level instability could still develop on Sunday and move over
the area. Generally, this will support cumulus development over
elevated terrain. Slight (10-15%) thunderstorm chances are in the
forecast across Siskiyou, Modoc, and southern Klamath and Lake
counties. Under these conditions, smoke plumes or pyro-cumulus may
be possible as well.

Dry conditions continue and temperatures may cool on Thursday and
Friday, although daytime highs would remain up to 10 degrees
above seasonal averages. -TAD

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.

CA...None.

PACIFIC COASTAL WATERS...None.

&&

$$

ZZZ/ZZZ/ZZZ